<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            width: 300px;
            height: 300px;
            border: 10px solid red;
            /*background-image: url("images/img.jpg");*/
            /*background-repeat: no-repeat;*/
            /*background-position: left top;*/
            /*background-attachment: scroll;*/
            background: no-repeat green url("images/img.jpg")  center top;  /*复合样式*/
        }
    </style>
</head>
<body>

    <!--
            background复合样式，顺便是可以颠倒的；
    -->
    <div></div>
</body>
</html>